Although RSV vaccine development dates back to the 1960s, there are no authorized vaccines. But both GSK and Pfizer have recently released positive Phase 3 data for their candidates and are progressing them through the regulatory process.
Yesterday, GSK announced that the FDA has accepted its Biologics License Application (BLA) for its RSV older adult vaccine candidate with Priority Review – meaning the FDA will expedite the review of the BLA and reduce the review period by four months. That means the Prescription Drug User Fee Act date for GSK’s application has been set as May 3, 2023.
GSK Phase 3 trial for RSV vaccine candidate in older adults
- In data published last month, GSK reported overall vaccine efficacy of 82.6% for its vaccine, with consistent efficacy against RSV A and B strains. The vaccine has a ‘favorable safety profile’.
- This candidate contains a recombinant subunit prefusion RSV F glycoprotein antigen (RSVPreF3) combined with GSK’s proprietary AS01E adjuvant.
- In the EU, the European Medicines Agency has accepted the vaccine’s marketing authorisation application under accelerated assessment, with a decision anticipated in Q3 2023. A new drug application has also been accepted by the Japanese Ministry of Health, Labour and Welfare.
Pfizer Phase 3 trial for RSV vaccine candidate in older adults
- In data published in August, Pfizer reported vaccine efficacy of 85.7% in participants aged 60+ with more severe disease primary endpoint of lower respiratory tract illness (LRTI-RSV) defined by analysis of three or more RSV-associated symptoms. The vaccine was ‘well-tolerated with no safety concerns’.
- The bivalent vaccine candidate is composed of two preF proteins selected to optimize protection against RSV A and B strains.
- At the time, Pfizer stated its intention to submit for regulatory approval in fall 2022.
Pfizer champions maternal RSV candidate
While Pfizer looks set to come in behind GSK in the RSV vaccine for older adults, it champions its position as the only company with investigational vaccines being prepared for regulatory applications for both infants through maternal immunization and older adults to help protect against RSV (In February this year, GSK halted trials for its RSV maternal vaccine candidate).
Earlier this week, Pfizer announced positive top-line data from its Phase 3 trials for its maternal RSV vaccine, which is administered to pregnant participants to help protect their infants from RSV disease after birth. The observed efficacy for severe medically attended lower respiratory tract illness was 81.8% through the first 90 days of life; with ‘substantial efficacy’ of 69.4% in infants over a six month follow-up period. Pfizer intends to submit a BLA for this vaccine by the end of the year.
“There is the potential that, subject to regulatory approval, by late 2023 or early 2024 we could have the only RSV maternal vaccine on the market, along with an RSV vaccine for older adults that has high efficacy and is well-tolerated with no safety concerns,” said Albert Bourla, Pfizer’s CEO, speaking in the company’s Q3 earnings call on Tuesday.
“Combined, the two indications represent a potential multibillion-dollar peak revenue opportunity, if approved, especially with our highly respected Primary Care sales force executing the launches. Including the RSV antiviral investigational candidates we acquired with ReViral [acquired earlier this year with candidates including Sisunatovir], we aim to have end-to-end solutions – with both preventative vaccines and therapeutics to treat those infected with RSV.”
Moderna’s mRNA candidate mRNA-1345 entered Phase 3 trials for adults aged 60+ in February, with the FDA having granted Fast Track designation for the vaccine. Bavarian Nordic’s candidate entered Phase 3 trials in April while Johnson & Johnson’s candidate (which has FDA Breakthrough Therapy Designation) announced its Phase 3 trial in September last year.
